1. Field of the Invention
This invention relates to a white or light-colored lubricating composition for use in warm and hot forging.
2. Description of the Prior Art
In warm and hot forging, which comprises heating and forging a metallic or alloy material blank, the die is kept heated at a temperature in the range of 100.degree. to 400.degree. C. during the forging operation. This forging requires the use of a heat resistant lubricant. A black lubricant, e.g., having an inorganic solid lubricant graphite or molybdenum disulfide, dispersed in either water, a mineral oil, or a synthetic oil. Such a solid lubricant exhibits outstanding lubricity at elevated temperatures.
However, since the black lubricant entails problems from the standpoint of working environments such as smearing of the site of use or betraying electroconductivity, there has been expressed a desire to utilize a harmless white lubricant. The conventional white forging quality lubricant, however, has the problem of a high coefficient of friction at the warm and hot forging temperatures as compared with the lubricant such as of graphite.
The coefficients of friction which the conventional black lubricants exhibit at prevalent warm and hot forging temperatures are not sufficiently small. The lubricants have the possibility of being seized by the die and do not always permit fully satisfactory release of a forged product from the die.